Anatomy Flashcards

1
Q

What are the 2 main groups of back muscles

A

Extrinsic: trapezius, lattismus dorsi, elevator scapulae, rhomboids, serratus posterior

Intrinsic (superficial layer, intermediate layer and deep) - these muscles produce movement and maintain posture inc erector spinae

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2
Q

Innervation of intrinsic back muscles

A

Posterior rami of spinal nerves

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3
Q

3 groups of intrinsic back muscles

A

Superficial: splenius, cervicis, splenius capititis)

Intermediate: erector spinae

Deep: transversospinal, semispinalis,

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4
Q

What are the different curvatures of the back

A

Lordosis (secondary curve- neck and lower back)

Kyphosis (primary curve - upper back and gluteus region)

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5
Q

What is cauda equine syndrome

A

Rare and severe type of spinal stenosis where all of the nerves in the lower back suddenly become severely compromised

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6
Q

Where are the adrenals located

A

Superior to the kidneys in the renal fascia and posterior to parts of the diaphragm

Right is posterior to the liver and IVC
Left is posterior to the stomach and pancreas

Right is pyramidal in shape; left is semilunar and slightly larger

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7
Q

What are the 3 layers of the outer cortex of the adrenal gland

A
  • embryological origin (mesoderm) similar to gonads
  • secretes steroid hormones with cholesterol precursors
  • secretion controlled by pituitary

Mineralocorticoids eg aldosterone (RAAS system)
Glucocorticoids eg cortisol and corticocosterol (ACTH from pituitary)
Androgenic steroids

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8
Q

Describe the inner medulla of the adrenal gland

A
  • Embryology from neural crest (similar to sympathetic nervous system)
  • Neuroendocrine
  • secretes catecholamines: adrenaline and noradrenaline
  • secretion is under SNS control - augments the SNS response (rapid)
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9
Q

What are the zones of the Cortex

A

Zona glomerulosa (mineralcorticoids) - blobs

Zona fasiculata (glucocorticoids) - strings

Zona reticularis (androgens) - networks

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10
Q

Blood supply of the adrenals

A

Arteries: 3 suprarenals each side

  • superior (from phrenic)
  • middle (from AA)
  • inferior (from renal arteries)

Veins: 1 each side

  • right - IVC
  • left - left renal vein
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11
Q

Drainage of adrenals

A

Arterioles from capsular arteries give rise to sinusoidal capillaries which drain into a medullary vein

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12
Q

What is secretion of the adrenals controlled by

A

Preganglionic neurons
The secretory cell is functionally equivalent to the postganglionic neurons of the SNS. Therefore secretions can be quickly released

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13
Q

Pathology of the cortex

A

Hypoadrenalism: Addison’s disease (no secretion of any hormones)

Hyperadrenalism: oversecretion 
Mineralcorticoids: conn’s syndrome 
Glucocorticoids: Cushing’s syndrome 
Malignant tumour: all 3 hyperstimulated 
Neuroendocrine lung tumour: XS glucocorticoids
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14
Q

What is phaeochromocytoma

A

Rare cause of secondary hypertension

Mostly benign adrenal tumour of neuroectodermal origin

Produces excessive catecholamines, causing hypertension which is continuous or sporadic

Can be dangerously high

Can cause lethal disease due to cardiovascular complications eg during surgical and obstetric procedures

Symptoms: headache, excessive sweating and palpitations

Diagnosis: urinary catecholamines or metabolites (not usually plasma)

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15
Q

Describe location of pelvis

A

Inferoposterior to abdomen
Part of the trunk
Area of transition between trunk and lower limbs
Compartment surrounded by bony pelvis

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16
Q

2 areas of the pelvis

A

Greater (false) pelvis - superior to pelvic inlet

Lesser (true) pelvis - runs between pelvic inlet and outlet - provides Bony framework for peritoneum

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17
Q

What is the pelvic girdle

A

Connects vertebral column to 2 femurs

Made of 3 bones

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18
Q

What is the subpubic angle

A

Defined by 2 bones either side (ischio pubic rami)

Degree of angle differs between males and females

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19
Q

Surface landmarks of bony pelvis

A

Iliac crest L4
Posterior superior iliac spine
2 dimples overlying sacrum (triangular region)
Coccyx

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20
Q

Characteristic features of male pelvis

A

Pelvic girdle is heavier and thicker and more prominent bony landmarks
Greater pelvis (superior to pelvic inlet) is quite deep
Lesser pelvis is quite deep and narrow
Sacral promontry will stick out and is quite narrow
Obturator foramen has a more rounded shape
Acetabulum is larger

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21
Q

Characteristic features of female pelvis

A

Greater pelvis is quite shallow
Lesser pelvis is shallow and wide
Pelvic inlet is oval, rounded and wide in the female- sacral promontry sticks out less than in males
Pelvic outlet larger (due to childbirth)
Sub pubic angle is wider (above 80 degrees)
Obturator foramen is more oval in shape

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22
Q

What are the endocrine parts of the pancreas

A

Islets of langerhans

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23
Q

Why does pancreas only comprise 1-2% of volume but receives 20% of blood supply

A

This disproportion is because of the high capillary network needed for hormone uptake

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24
Q

What are the exocrine parts of the pancreas

A

Duct cells that secrete aqueous NaHCO3 solution and acinar cells that secrete digestive enzymes

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25
Q

What are the islets of the pancreas

A

Evenly distributed throughout the organ
25% in head, 25% in uncinate process, 20% in body, 30% in tail

Each islet has up to 3 arterioles, expanding into an extensive network of fenestrated capillaries draining into up to 6 venules

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26
Q

What do the different cell types secrete

A

Beta - insulin and amylin (70%)
Alpha - glucagon (20%)
Delta - somatostatin (5-10%)
PP cells - containing pancreatic polypeptide (1-2%) sometimes called F cells

Not distinguishable from each other except via immunostaining

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27
Q

How does the pancreas develop embryonically

A

Embryonic duodenum and endoderm come together by rotation of the GI tract that brings bile duct round

Embryonic ductal epithelium can differentiate into endocrine or exocrine part

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28
Q

Blood supply of the pancreas

A

Splenic and superior and inferior pancreaticoduodenal arteries

Veins tributaries of splenic and superior mesenteric portal

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29
Q

Innervation of the pancreas

A

Sympathetic (abdominopelvic splanchic)

Parasympathetic (vagal)

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30
Q

Why is the pancreas vulnerable for injury

A

Not very well protected
Has a soft consistency
Not easily accessible for surgery

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31
Q

Why is pancreatic cancer so serious and life threatening

A

Difficult to reach for surgery
Doesn’t show symptoms early on
Close proximity to kidney and spleen (spread) due to extensive blood and lymph supply

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32
Q

What are the different chains of an insulin molecule

A
A chain (21 aa) 
B chain (30 aa) 
C peptide (31aa)+ 4 when connected to a and b
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33
Q

Where is insulin synthesised

A

B cells

Half life of 5-9 mins
Initially as proinsulin which has 86 aa in humans

34
Q

Function of C peptide

A

Links A and B chain but has no biological activity however emerging research data suggests otherwise

35
Q

What is the main physiological regulator of insulin

A

Blood glucose >5mM - rise in ATP : ADP ratio results in closure of ATP sensitive K + channels, membrane depolarisation, leading to opening of voltage gated Ca2+ channels - increased insulin resistance

Glucose is metabolised, phosphate is added to ADP to make high energy ATP

36
Q

Neural control of insulin release

A

Sympathetic NS- B-adrenoceptor increases IR ; a2-adrenoceptor decreases IR

Parasympathetic NS - muscarinic receptors increase IR

37
Q

Action of insulin

A

Promotes growth and development (particularly intrauterine)
Promotes cellular uptake of K+ via Na+-K_ ATPase pump
Promotes uptake and utilisation of glucose in skeletal muscle and adipose
Promotes fuel storage ( anabolic) - increases rate of synthesis and storage of energy reserves and of protein

38
Q

What is glucagon

A

A peptide hormone , synthesised in islet a cells
Release is stimulated by low blood glucose (<3.5mM)
Para and sympathetic NSs (both branches) and aa

Inhibited by high blood glucose, insulin and somatostatin

Actions: opposite to those of insulin

39
Q

Main actions of glucagon

A

Raise blood glucose
Stimulate hepatic glycogenolysis
Stimulate hepatic gluconeogenesis
Stimulate lipolysis (triglyceride synthesis)

40
Q

What happens when there is a rise in blood glucose

A

Stimulation of B cells to increase insulin and inhibition of a cells to decrease glucagon which then decreases blood glucose to normal

41
Q

What happens when there is a decrease in blood glucose

A

Stimulation of a cells which leads to an increase in glucagon and inhibition of B cells to decrease insulin which then increases blood glucose back to normal

42
Q

What is somatostatin

A

Peptide hormone
Synthesised in islet gamma cells (14aa) also in CNA and GIT (28aa)

Inhibits both glucagon and insulin secretion by a paracrine mechanism

43
Q

What are the roles of adrenaline, cortisol and GH in fuel metabolism

A

Adrenaline - provision of energy for emergencies and exercise

Cortisol - mobilisation of fuels during adaptation to stress

GH - promotion of growth (normally smaller role in metabolism)

44
Q

What are the 2 types of diabetes

A

Type 1 : insulin deficiency

Type 2: impaired B cell function and or loss of insulin sensitivity (insulin resistance)

45
Q

Symptoms of both T1 and T2 diabetes

A

Glucosuria (glucose in urine - large glucose load in filtrate so is excreted in urine)

Polyuria ( glucose holds water with it leading to frequent urination)

Thirst (due to diuresis)

Fatigue and malaise ( high glucose but lacked insulin means glucose cant be used properly)

Blurred vision (due to chronic hyperglycaemia)

Infections eg candidiasis (glucose provides optimum conditions for bacteria)

46
Q

Symptoms of ONLY T1

A

Weight loss (less anabolic effects of insulin - lose fats and muscle)

Ketoacidosis (N&V, acetone breath- due to body trying to deal with acidosis)

47
Q

Symptoms of only T2

A

Complications (secondary)

Altered mental status (due to chronic hyperglycaemia)

48
Q

What are the glucose levels for making a diagnosis

A

Fasting > 7.0 mmol/L
Random > 11.1 mmol/L
Plasma glucose concentration > 11.1 mmol/L, 2h after 75g glucose in an oral glucose tolerance test

Or HbA1c > 48 mmol/mol (or 6.5%) normal = 20-42mmol/mol 4-6%

49
Q

What is the HbA 1c test

A

Glycated or glycosylated haemoglobin

- indicator of glycaemic control during the previous 2-3 months

50
Q

How do you diagnose ‘pre diabetes’ / impaired glucose tolerance

A

Impaired glucose tolerance:
Fasting <7 mmol/L
Random or OGTT >7.8 but < 11.1 mmol/L

Impaired fasting glycaemia
Fasting >6.1mmol/L but <7mmol/L

Risk categories for future diabetes and / or CVD ‘pre diabetes’ HbA1c :42-47 mmol/mol

51
Q

What is type 1 diabetes

A

An autoimmune condition (autoantibodies may be detected)
Progressive destruction of islet B cells
0.6% of uk population
Onset usually <40 years

Rapid onset
No complications at diagnosis
Weight - normal or loss

Tendency to ketosis
Treatment with insulin, regular exercise, healthy diet

52
Q

What is ketogenesis

A

Synthesis of ketone bodies by the liver from fatty acid breakdown products

2x acetyl CoA = acetoacetate
B-hydroxybutyrate and acetone

Normally a small amount in the blood but in starvation and type 1 DM -> ketosis -> metabolic acidosis (decrease in blood pH )

53
Q

Sources of insulin

A

Animal: porcine , bovine

Human: semi-synthetic - enzymatically modified human insulin
Recombinant E. coli , yeast

Insulin is classified according to duration of action

54
Q

Different types of insulin

A

Short acting
- soluble

Intermediate acting
- isophane (complexed with protamine, NPH)

Long acting

  • insulin zinc suspension
  • analogues (glargine, detemir)

Biphasic (pre mixed)
- mix of short and intermediate acting insulin’s

55
Q

Why should you rotate the injection site

A

To avoid lipodystrophy which leads to erratic insulin absorption of that part of the skin and altered fat distribution under the skin

56
Q

When are iv insulin injections used

A

Short acting soluble insulin for urgent treatment

For fine control in serious illness 
In diabetic ketoacidosis 
In surgery (peri operative)
57
Q

What is cell replacement therapy

A

Islet transplantation from human cadaver

Requirement for immunosuppressive to prevent rejection
Limited supply of islets for transplantation

58
Q

What is type 2 diabetes

A

Relative insulin deficiency (impaired B cell function) and / or insulin deficiency
5.4% of population
Onset usually >40 years

Gradual onset
Complications present in 25% of patients at time of diagnosis
Usually overweight
No ketones in urine (only at really advanced)

59
Q

Secondary causes of DM

A

Endocrine: Cushing’s (excess cortisol), acromegaly (excess GH), phaeochromocytoma (excess adrenaline)

Pancreatic disease
- chronic pancreatitis, surgery, cystic fibrosis, tumour either via loss of function or loss of tissue

Genetic disorders: Down’s syndrome, prader willi

Drug induced: steroids, beta blockers, diuretics

60
Q

Lifestyle changes to help diabetes

A

Diet - healthy (weight loss if necessary 5-10%)
Lifestyle
Exercise - improves insulin sensitivity and weight loss
Smoking cessation - decreases CV risk

61
Q

Strategy of treatment for T2 DM

A

Diet / lifestyle interventions
Metformin (caution in renal impairment) or SU or DPP-4i or pioglitazone or SGLT-2i
Then dual therapy (2 drugs)
Then triple therapy (start insulin)
Then intensify insulin regime or add drugs

62
Q

Mode of action of metformin

A

Not clear
Is thought to Activates AMP kinase
Decreases gluconeogenesis and increase glucose utlilisation

63
Q

Mode of action of sodium glucose co transporter 2 (SGLT-2) inhibitors

A

Eg dapaglifozin, canagliflozin
Inhibit renal glucose reabsorption
- reversible inhibit SGLT-2 in renal PCT to reduce glucose reabsorption and increase urinary glucose excretion - decrease in blood glucose

64
Q

Describe the pituitary gland

A

1cm bean shaped gland

Located in a cavity of the sphenoid bone (sella turcica)

Under the control of the hypothalamus

2 parts: anterior and posterior have different embryological origins

65
Q

Why is the pituitary in 2 separate pieces

A

Because it forms from an ectodermal upgrowth (rathke’s pouch) from the roof of the primitive mouth and an neuroectodermal downgrowth of the brain

66
Q

Describe the posterior lobe of the pituitary gland

A

Neural tissue (growth down from the hypothalamus) and attached to it via the pituitary stalk
Secretes 2 hormones:
ADH and oxytocin

Synthesised in the cell bodies of the neuron and stored in the terminal ends of the axons
Secreted by nuerosecretion
Acts on non endocrine tissues
Blood supply from middle and inferior hypophyseal arteries

67
Q

Describe the anterior lobe of the pituitary Gland

A

Glandular tissue growing up from the embryological epithelium of the roof of the mouth (rathkes pouch)
Main bulk of the anterior pituitary is called the pars distalis

Curls around the pituitary stalk (pars tuberalis)

The pars intermedia is the piece next to the posterior pituitary and can be separated from the rest by the vestiges of rathkes pouch. It secretes melanocyte stimulating hormone

68
Q

What are chromophobes of the pituitary gland

A

Immature with only a few hormones

Recently released most of their hormones

Waiting in reserve so don’t have a lot of hormones

(Either one of these or all)

69
Q

In the anterior pituitary what colours are the different cells

A

Acidophils - pink
Basophils - purple
Chromophobes - pale

Interspersed with plentiful capillaries

70
Q

Ultrastructure of the anterior pituitary

A

Presence of prominent storage granules, nucleus with nucleolus, mitochondria, endoplasmic reticulum

71
Q

What are chromophils

A

Actively secreting cells

72
Q

2 different types of acidophils of the pituitary and what they secrete

A

Somatotrophs - GH

Lactotrophs - prolactin

73
Q

2 different types of basophils

A

Corticotrophs - ACTH + others

Thyrotrophs - TSH

74
Q

Describe secretion from the anterior pituitary

A

Mediated by hypothalamic releasing hormones from the median eminence of the hypothalamus

Blood supply from super hypophyseal arteries (internal carotids)

Via the pituitary portal system - external plexus collects from hypothalamus

This carries stimulating hormones directly from the hypothalamus to the cells of the anterior pituitary

Pituitary hormones are secreted into the lower capillary bed and drain into the hypophyseal veins

Blood supply enters via the pituitary stalk (can be damaged in head injury)

75
Q

Clinical relevance of pituitary tumours

A

Relatively common they are frequently benign but cause problems because of pressure on surrounding structures

76
Q

What is bilateral hemianopia

A

Temporal field of view lost (peripheral vision)

77
Q

Describe tumours of the pituitary gland

A

Relatively common
Almost all are benign and do not spread (adenoma)
Size of an orange
Dangerous as can compress parts of the brain

Pituitary is relatively accessible by nasal cavity and saphenoid bone

78
Q

What hormone is oversecreted in a pituitary tumour

A

Growth

79
Q

What is the levator ani

A

Has a number of subdivisons which are defined as individual muscles in most textbooks but are difficult to distinguish

80
Q

Why are the testes outside the pelvis

A

Because sperm production is optimal at temperatures 2-4c below body temperature

81
Q

What is the perineum

A

The area on the outside of the pelvic floor
Region between vulva / scrotum and perineal body and anal region
Perineal membrane is part of the perineum divides the region of the urogenital triangle into a superficial and a deep pouch

82
Q

Blood supply and nerves in the pelvis

A

Supply to pelvic organs via branches of internal iliac vessels

Other branches of the internal iliac go to glutei
The veins of the pelvic organs form interlinked plexus resulting in Portocaval anastomoses via the superior rectal vein

Lymph vessels follow blood vessels although the direction of pelvic lymph flow is towards the nodes around the common iliac vessels
Pelvic organs are innervated by the plexus of the autonomic nervous system